The Ornish diet was developed in the 1970s by Dean Ornish, M.D., a clinical professor of medicine at the University of California, San Francisco. It focuses on low-fat foods and encourages followers to zero in on plant-based foods like fruits and vegetables, whole grains, and legumes, Cording says. It’s a lacto-ovo vegetarian diet, meaning it discourages followers from eating meat, fish, or poultry, but allows for dairy products and eggs.
People on the diet are also encouraged to limit “bad carbs” like refined carbs, sugar, white flour, and white rice, while focusing on healthy fats from fish oil, nuts, and seeds, along with plant-based proteins like egg whites, tofu, beans, and legumes, per the Ornish Lifestyle Medicine website.
How it works for weight loss: The diet is “really about food quality and nutrient density,” which can help lead to weight loss, Cording says. On a basic level, she points out, low-fat foods tend to be lower in calories and can help someone lose weight. “It can be helpful for weight loss by default,” Cording says.